CDK5RAP3 and head and neck squamous cell carcinoma: To determine if LZAP activity was cell type specific, p38 phosphorylation after LZAP knockdown and IL-1β stimulation was determined in 1 breast cancer cell line (MCF-7) and in 2 head and neck squamous cell carcinoma lines (UM-SCC47, FaDu).As observed in U2OS cells, siRNA-mediated loss of LZAP was associated with increased p38 phosphorylation (Fig. 3E).